Whistleblower Web site Wikileaks today announced that it has temporarily suspended operations due to financial constraints.

In a brief note posted on its site, Wikileaks blamed an "unlawful financial blockade" by several U.S. financial services companies for its situation. It also urged supporters to donate to its cause.

"We are forced to temporarily suspend publishing whilst we secure our economic survival," Wikileaks said in the post. "We cannot allow giant U.S. finance companies to decide how the whole world votes with its pocket. Our battles are costly. We need your support to fight back."

Wikileaks claims that it has been the target of "aggressive retaliation" from several groups for publishing tens of thousands of classified U.S. State Department cables starting last November.

The blockade, as Wikileaks terms it, has been going on since December 2010 and has "destroyed 95% of our revenue," Wikileaks said. The site has been forced to run on cash reserves for the past 11 months, it added.

The site claims that the actions by the financial services companies are politically motivated and designed to push Wikileaks out of existence.

A chart on its website shows that donations to Wikileaks have virtually flat-lined since January, 2011, after peaking a month earlier.

"The blockade is outside of any accountable, public process. It is without democratic oversight or transparency," Wikileaks lamented.

The move to shutter the site at least temporarily is not surprising.

Wikileaks and its founder, Julian Assange, have been under tremendous pressure since the site began posting nearly a quarter of a million leaked State Department cables last November.

Soon after the site began publishing the documents, Visa, MasterCard, PayPal and others terminated services to Wikileaks, citing terms of service violations.

Both MasterCard Europe and Visa Europe face complaints that the move to terminate the services violates European Union antitrust laws.

Wikileaks has also commenced what it calls as pre-litigation action against the financial services companies in several countries including Denmark, Belgium, United Kingdom and the U.S.